Method and apparatus for storing digital information in fluid medium

ABSTRACT

A fluidic memory system which is compatible with conventional fluidic logic elements includes a number of pumps for selectively introducing quanta or segments of any of a plurality of fluids into the input end of a storage tube in response to a digital input signal. The different fluids are generally immiscible as used in the system and are distinguishable from each other by characteristic and detectable differences in a physical property, each fluid being representative of a discrete data level of the input signal. A pattern of fluid quanta is thus formed in sequential relation in the tube to provide a &#39;&#39;&#39;&#39;permanent&#39;&#39;&#39;&#39; or &#39;&#39;&#39;&#39;non-volatile&#39;&#39;&#39;&#39; representation of the input signal. The fluids remain separate, although adjacent quanta are contiguous, as they are advanced through the tube. As the fluid pattern is transmitted along the tube the selected physical characteristics of the fluid quanta or segments is sensed by a detector and signals are generated which correspond with the data level of each fluid being sensed. The signal pattern may then be recirculated, or a new pattern may be introduced into the memory tube. Fluids discharged at the output end of the tube may be separated and returned to their respective pumps. Modifications including a scanning system for reading the data at a faster rate then the propagation rate of the individual quanta are also described.

United States Patent .19.

Jones METHOD AND APPARATUS FOR STORING DIGITAL INFORMATION IN FLUID MEDIUM [75] Inventor:

Alan Richardson Jones, Miami, Fla. Assignee: Dade Reagents, Inc., Miami, Fla. Filed: July 15, 1968 Appl. No.: 745,029 A US. Cl 137/1, 137/806, 235/201 R Int. Cl. G06d l/ Field of Search 235/200, 201; 137/1, 81.5,

[56] References Cited UNITED STATES PATENTS 1,382,782 2/1964 France 235/201 OTHER PUBLICATIONS Truslove, D. J Fluid Decimal Counter, IBM Technical Disclosure Bulletin, Vol. 6, No. 3, August 1963.

Primary Examiner-William R. Cline Attorney, Agent, or Firm-Dawson, Tilton, Fallon and Lungmus 11] 3,834,411 Sept. 10, 1974 [57] ABSTRACT A fluidic memory system which is compatible with conventional fluidic logic elements includes a number of pumps for selectively introducing quanta or segments of any of a plurality of fluids into the input end of a storage tube in response to a digital input signal. The different fluids are generally immiscible as used in the system and are distinguishable from each other by characteristic and detectable differences in a physical property, each fluid being representative of a discrete data level of the input signal. A pattern of fluid quanta is thus formed in sequential relation in the tube to pro vide a permanent" or non-volatile representation of the input signal. The fluids remain separate, although adjacent quanta are contiguous, as they are advanced through the tube. As the fluid pattern is transmitted along the tube the selected physical characteristics of the fluid quanta or segments is sensed by a detector and signals are generated which correspond with the data level of each fluid being sensed. The signal pattern may then be recirculated, or a new pattern may be introduced into the memory tube. Fluids discharged at the output end of the tube may be separated and returned to their respective pumps. Modifications including a scanning system for reading the data at a faster rate then the propagation rate of the individual quanta are also described.

Claims, 15 Drawing Figures 22 13 U Dull, PUMP jg 15 35 26 (H O) i 2 VALVE i0 {2 omven 1i lllOllllloll I 27 PUMP I VALVE 18 Q) l CLOCK PULSE 30 32 GENERATOR WRITE/ nzcmcuure msmmwwwn 3.834.411

SCANNING READOUT CIRCUIT CLOCK z. somume CLOCK REYADOUT TWP! 142' N 51%? Y A #6 v III 9 I I I DISCRIMINATOR j f H I L l fljacimzm bws BACKGROUND The present invention relates to memory systems; more particularly, it relates to a system for storing discrete bits of information in a manner which is compatible with conventional fluidic logic elements, such as AND gates and NOR gates.

There are many known ways for storing digital information electronically, such as magnetic tapes, magnetic discs or drums, and random-access core memories to name a few. One of the very important aspects of these electronic or magnetic memory systems is that they are compatible with conventional electronic circuitry for reading the information stored in the memory, amplifying it, and otherwise operating on it.

F luidic logic elements are presently of great interest tosystems designers for the reliability, simplicity, and relatively low cost they offer as compared with their electronic counterparts. Fluidic gates are known which are capable of performing all the logic and computation functions of electronic circuitry; however, operation is usually at a much lower speed. Fluidic memory systems offering the same reliability and relatively low cost are not generally available; and the present invention concerns such a fluidic memory system which is not only compatible with fluidic logic elements as well as electrical logic circuits, but which offers the reliability and simplicity characterized by fluidic logic elements.

SUMMARY The memory system of the present invention includes an elongated conduit tube having a closed cross section for containing and transmitting fluid. First and second pumps (in the case of a binary logic system although the invention is not so limited) are arranged to introduce predetermined quanta of different fluids into the input terminal of the tube at mutually exclusive times.

v The fluids are generally immiscible and are distinguishable from each other by difference or variations in a detectable physical property which is representative of discrete data levels. As the fluid quanta are selectively introduced into the tube according to a predetermined pattern representative of the information to be stored, and as such quanta advance through the tube, the individual quanta of fluid remain separate, that is, they retain their integrity and identity even though adjacent quanta are contiguous. The entire fluid pattern advances through the tube in incremental steps as new quanta are introduced by one or the other of the pumps.

A sensor is located intermediate the length of the tube for sensing the physical characteristic which distinguishes the fluids as the segments or quanta advance along the tube and the sensor generates a signal corresponding to the data level of each particular fluid being sensed. The system is adapted so that the same data pattern may be recirculated through the fluidic memory system or new data may be introduced in place of it. The fluids may be separated in a reservoir at the output end of the memory tube and routed back to their associated pump. A clock pulse generator determines the system timing in introducing the fluid quanta into the memory tube and in reading the information from the tube.

The memory tube therefore acts as a delay line, delaying the stored pattern for a predetermined time in relation to the clock pulse generator. As such, the tube acts as a memory device for the information pattern and may also be used as a shift register because the sig nal pattern is propagated along the tube with the data pattern preserved. To conserve space the delay tube may be coiled or otherwise compacted to increase the storage density of the information. It will also be appreciated that if system power is lost the information in the memory tube does not disintegrate as long as the seg ments or quanta retain their integrity or identity. That is, the memory system is permanent or nonvolatile as those terms are used in the computer art.

A further advantage of the present memory system is that although the propagation rate of the individual quanta is defined or limited by the clock pulse generator, nevertheless, the length of the tube may be scanned electronically at a much greater rate, thus rendering the memory asynchronous, if desired. Further, any number of such tubes may be arranged in parallel, each containing its own information pattern to form a memory matrix. In this manner, a given location for each tube may form a word composed of n bits (n being the number of parallel tubes) and the scanning may take place transversely of the flow direction. Further, with a more elaborate system of parallel tubes and scanning sensors, a random access memory is possible.

Other features and advantages of the present invention will be obvious to persons skilled in the art from the following detailed description of preferred embodiments accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.

THE DRAWING FIG. 1 is a schematic diagram, partially in block form, of a memory system according to the present invention;

FIGS. 2A-2D represent various idealized waveforms of the system of FIG. 1 on a common time base;

FIGS. 3-4 are schematic diagrams of alternative memory systems according to the' present invention with accompanying electronic scanning read out elements.

FIG. 5 is a memory system according to the present invention which is based upon a ternary number systems;

FIG. 6 is a schematic diagram, partially in block form, of another alternative embodiment of the inventive memory system;

FIGS. 7A-7E are idealized waveforms of various elements of FIG. 6 on a common time base; and

FIG. 8 shows a modification of the memory tube which may be included in the inventive memory system.

DETAILED DESCRIPTION Turning now to FIG. 1, an elongated memory tube of closed cross section and any desired length is generally designated by reference numeral 10. An input end of the memory tube 10 is generally designated 11; and an output end is generally designated 12. A first pump 13 communicates by means of a conduit 14 and a unidirectional valve 15 with the input 11 of the tube 10. A

second pump 16 also communicates by means of a conduit l7 and a unidirectional valve 18 with the input 11 of the tube 10. 1*

A reservoir 19 communicates with the output 12 of the tube to receive fluids which are pumped through the tube. As schematically illustrated in FIG. 1, reservoir 19 contains a first fluid 20 and a second fluid 21. For purposes of illustrating the present invention, it will be assumed that liquid 20 is water and that liquid 21 is mercury. Since these liquids are immiscible and have significantly different specific gravities, they will separate in the reservoir 19 under force of gravity with the lighter fluid (water) rising to the top. A return conduit 22 communicating with the top of the reservoir 19 couples or returns the water 20 back to the input of the pump 13; and a similar return conduit 23 communicating with the bottom of the reservoir 19 couples or returns the mercury back to the pump 16. The quantity of each fluid stored by thereservoir should be greater than the capacity of its associated conduit, pump. and the memory tube so as not to exhaust its supply.

Each of the pumps 13 and 16 ideally has the exact same stroke volume so that a quantum or segment of water introduced into the memory tube 10 by means of the pump 13 would have exactly the same length as a like quantum of mercury introduced by the pump 16. It has beenassumed for convenience of description that the diameter of the memory tube 10 is uniform throughout its length; however, as will be more fully explained hereafter, this need not necessarily be'the case.

The pumps 13 and 16 are selectively energized by means of a driver circuit 25 having complementary output terminals 26 and 27. That is, for a given voltage required to energize either of the pumps 13 or 16, only one of the leads 26 or 27 will exhibit that voltage, the other lead having either a voltage capable of operating the pump or being at ground or common level.

A clock pulse generator 29 feeds the driver circuit 25 as well as an enable input of an amplifier circuit 30. The information to be transmitted through the memory tube 10 by means of the media incrementally flowing therein is fed along a line 31 .which is connected to an information input of the driver 25. The information input is routed to the line 31 through a conventional gate circuit 32 receiving one signal input from the output of the amplifier and receiving another signal input schematically designated DATA IN. The Data In terminal represents the introduction of new datainto the memory system. The two input leads to the gate 32 are also mutually exclusive; and the selection of which input signal lead is routed to the output line 31 to the driver 25 is determined by means of a Write/Recirculate Circuit schematically designated by the block 33 which performs a simple switching function.

Mercury and water have been selected for illustrative purposes because, in addition to being immiscible, they are clearly distinguishable by at least one readily detectable physical property optical density. To distinguish between the two liquids optically, a light source 35 which generates a collimated beam of light 36 is directed to intersect or pass through the fluid contained in the memory tube 10 and to impinge upon a photocell 37, the output of which is coupled to the signal input of the amplifier 30. Toward this end, the material comprising the memory tube 10 may be transparent throughout or it may be generally opaque and provided with windows for transmission of the light beam 36. Assuming,'for illustration purposes, that a quantum of mercury represents a logic level of l and that a quantum of water represents the logic level of 0," reading from right to left from the output terminal 12 of the tube 10, the stored data pattern is 101101. The placement of the optical sensor comprising the light source 35, the beam of light 36 and the photocell 37 may be at any of a number of locations along the tube 11. In the illustrated embodiment the placement is upstream of the output terminal 12 of memory tube 10 so that the entire stored pattern recited above will already have been read.

Turning now to FIGS. 2A-2D, the timing and operating of the system of FIG. 1 will be explained in greater detail. In FIG. 2A, there is shown a periodic series or train of positive pulses identified by reference numeral 40; and these represent the train of clock pulses at the output of the clock pulse generator 29. Assuming that the Write/Recirculate circuit 33 had previously energized the gate 32 to introduce new data into the memory tube, the waveform of FIG. 2B represents the input pulse signals from the driver 25 along the line 27 feeding the mercury pump 16. It is assumed that a relatively highvoltage energizes the pump to produce its predetermined stroke and that the data bits are entered into the memory tubes as set by the time base provided by the clock pulse generator 29. It will be appreciated that the output signal from the driver 25 to the water pump 13 is the complement of the waveform shown in FIG. 28, that is, the line 26 transmits a relatively low voltage level when the pump 16 is activated; and conversely, the line 26 will transmit a relatively high voltage to energize pump 13 when the signal line 27 is at a relatively low voltage. Further, although the signals energizing the pumps are illustrated as extending a full digit time, it is envisioned that the energizing pulses to the pumps will be somewhat less than this to insure the completion of a stroke without overlapping. This would propagate the fluid incrementally with the entire medium coming to a stop prior to each clock pulse. It will thus be apparent that the time base may be continuously variable over a wide range, for example, by having the clock pulse generator being a voltage controlled oscillator.

After the given quantum of fluid has been advanced incrementally along tube 10 to the sensing zone (which occurs at time interval t, following input as represented in FIGS. 2C and 2D) the photocell 37 produces an output voltage similar to that shown in FIG. 2C. That is, when a quantum of mercury passes between the source 35 and the photocell 37, the light beam 36 is interrupted thereby reducing the conductivity of the photocell 37 and increasingits anode voltage as indicated by the portion 41 of the waveform of FIG. 2C. When a quantum of water passes between the light 35 and the photocell 37, the light beam 36 will impinge on the photocell with greater intensity to increase the conductivity of the cellso that the output voltage of the photocell will become relatively low, as represented by reference numeral 42 of FIG. 2C.

As can be seen from the comparison of FIGS. 28 and 2C, the output signal of the photocell 37 is roughly similar to the output of the driver 25 delayed by the amount of time it takes for a quantum of fluid to be transmitted from the input 11 of the memory tube 10 to the sensor area. It will also be appreciated that the changed by adjusting the position of the lightsource 35- and its associated photocell 37. The output signal of the photocell 37 is then fed to the signal lead of the amplifier 30. The clock pulse generator 29 sends a strobe pulse to trigger the gating lead of the amplifier 30. Thus, when the next clock pulse is fed to the gate lead of the amplifier 30, its output will change according to the signal level at its signal lead. The output waveform of the amplifier 30 is seen in FIG. 2D and is essentially a repetition (delayed by t,) of the waveform of FIG. 2B which represents the input data. The output of the amplifier 30 may then be recirculated through the memory tube by means of the Write/Recirculate circuit 33, if desired.

As mentioned, the location of the light beam determines the relative phasing of the readout circuit and the strobe pulse. In the illustrated embodiment, the distance of the sensor from the input end of the tube is a multiple of the lengths of each fluid quantum or segment plus one half length. Here, the length assumed by each quantum is the same. By adjusting the position of the sensor longitudinally of the memory tube, the strobe time of the readout signal may be adjusted to achieve a maximum signal-to-noise ratio.

Turning now to FIG. 3, there is seen a plurality of memory tubes designated respectively D D D D. D and D The tubes D,D are arranged in parallel, and each is fed by means of a water pump and mercury pump as designated in connection with FIG. 1. They all may flow into a common reservoir if desired. However, the data bits are propagated through the tube similarly to the single tube shown in FIG. 1. The combined bits of each of the digit lines D -D for a given vertical column of these bits form a word, and these are designated W W in the drawing.

In this embodiment, there is a sensor for each of the tubes D -D and these are schematically designated by reference characters S 45, respectively. Each of the output lines from the sensors 8 -8 is fed to a scanning read-out circuit, schematically designated within the block 45, which also receives the clock pulse. The

scanning read-out circuit 45 contains a gated amplifier similar to the amplifier 30 of FIG. 1 together with a shift circuit capable of shifting the clock pulse received sequentially to each of the read-out amplifiers so that within a very short time (much less than the time re quired for a quarter of a bit to traverse the sensing area) all of the data bits comprising one word (W in the illustrated example) are read-out by the scanning read-out circuit. This is further illustrated schematically by the binary designation at the parallel read-out lines, reading from right to left, these signals read 101110. It can be seen that this is the electrical equivalent of the data represented in W, reading from top to bottom in the column comprising W Referring now to FIG. 4, the memory tube may also be sequentially read in a direction upstream (or downstream, if desired) of a given quantum of fluid. In FIG. 4, the memory tube is designated by reference 10; and each of seven sensors is generally indicated by reference characters S '-S respectively. Again, a scanning read-out circuit 45 which receives a clock pulse scans the seven parallel data inputs in predetermined sequence in a very rapid scanning relative to the flow rate of the fluid quanta.

FIG. 5 is a diagrammatic illustration of portions of the system of FIG. 1 except that the memory tube 10 is fed by three separate feed conduits l4, l7 and 46. Each of these conduits couples a different fluid to the memory tube; and the pumps are controlled by means of logic circuits similarto the system of FIG. 1 so that the memory tube is adapted to carry information of base three i.e. ternary system. In this case, the sensor is generally designated 50; and it feeds a discriminator circuit 48 which also receives a clock pulse and generates an output signal on one of three output lines representative of the data level presently being sensed.

Turning now to FIGS. 6 and 7AE, there is shown a modification of the system of FIG. 1 including a memory tube 10" having an input terminal 11 and an output terminal 12'. A water pump 13 is coupled to the memory tube input 11' through a conduit 14' and a unidirectional valve 15'. A second pump 16' is coupled to the input terminal 11' by means of a conduit 17 and a second unidirectional valve 18'. A reservoir 19 receives the output of the memory tube 10"; and again,

the two liquids are water, designated by reference nuf meral 20 and mercury, designated by reference numeral 21.

As in FIG. 1, the upper section of the reservoir 19' communicates with the pump 13; and the lower section of the reservoir 19 communicates with the pump 16'. The pumps 13 and 16' are driven by means of the driver circuit 25' which has a set input (S), and a reset input (R) and a trigger input (T). The output signals of the driver circuit 25 are again mutually exclusive signals so that only one of the pumps 13 or 16' is energized in a given time. A clock pulse generator 29 energizes a gate 32 and a mid-clock pulse generator 29a which may comprise a conventional monostable circuit. The gate 32, rather than having the single output of the previous embodiment has two separate output lines indicated by the lines 31- and 31", connected respectively to the reset and set inputs of the driver circuit 25'. The output signal of the mid-clock pulse generator 29a energizes the trigger input of the driver circuit 25 A Write-Recirculate control circuit 33 feeds the gate 32'.

'A first optical sensor is generally designated 50 and downstream of the optical sensor 50 is a second optical sensor 51. The output of the optical sensor 50 feeds the signal input of an amplifier and the output of the optical sensor 51 triggers a strobe pulse generator 52 which, in turn, feeds the gate input of the amplifier 30.

Turning now to FIGS. 7A-7E, the signal-processing operation of the system of FIG. 6 will be described in detail. In FIG. 7A, there is shown in solid line a train of clock pulses 53 which are generated by the clock pulse generator 29. Intermediate adjacent of the clock pulses 53, there is indicated in dashed line a mid-clock pulse 54 which is generated by the mid-clock pulse generator 29a and is fed to the trigger input of the driver circuit 25. For this embodiment, each data bit that is propagated through the memory tube 10 is composed of a quantum of mercury as well as a quantum of water; and if the mercury preceeds the water with a bit section, a convention is made that the data bit is a 1; whereas, if the water quantum preceeds the mercury quantum, the data bit is a 0. The function of the midclock pulse generator 29a and the mid-clock pulse 54 is to trigger the driver circuit into its complementary stage at the half-way mark between the clock pulse 53. Thus, the data is fed through the gate 32', either by means of recirculating the previously stored data or by entering new data; and if the data being written into the memory tube is a logic 1," the output line 31' of gate 32 will energize the set input lead of the driver circuit 25' which will generate an output signal or the output I line 27' to energize the mercury pump 16.

Midway between a clock interval, the mid-clock pulse generator 29a will generate an output pulse to trigger the driver to its complementary state so that the line 26' will then transmit a voltage'pulse to energize the pump 13. At this time, FIG. 78 indicates the voltage as might appear on the line 27 feeding the mercury pump 16 for the signal pattern 101101. Again, the output sensor 50 generates a continuous signal as indicated in FIG. 7C which is the duplication of the waveforms 78 delayed by the transit time of the fluid from the input 11' tothe location of the sensor 50. The output of the sensor 51 is located downstream of the sensor 50 by a length of the tube equivalent to a multiple of 1%. bit lengths so that the output of the strobe pulse generator 52 which is set to oscillate at the frequency of the clock pulse generator 29' is reset at a delay time of A bit length from the reading sensor 50.

As illustrated in FIG. 7D, the strobe ratio pulses 56 are delayed by one-fourth of the clock so as to occur midway between the narrowest pulse possible in the output of FIG. 7C. When the strobe pulse 56 occurs, if the output of FIG. 7C is a relatively high voltage, the output of amplifier 30 reduces to a relatively low level. The output of the amplifier 30 is shown in FIG. 7E; and assuming the original convention of a relative high voltage being a 1, the output matter can be seen to be 101110 (the final 1 not being illustrated).

This particular embodiment in which each data segment or quantum is composed of portions of at least two different fluids eliminates the possibilities of error which might otherwise arise should there be even a slight difference in strobe volumes of the respective pumps and should the unit be operated so that one of the pumps is energized more than the other-or others. Such an embodiment does not require the use of the main clock pulse generator to strobe-during reading. The information itself carries along the clock information thus obviating the need to accurately place the sensor at any particular location along the memory tube. An initial pulse pattern or a third type of fluid could be introduced into the memory tube 10 in order to set up the strobe pulse generator in proper phase relation with the sensor 50.

Turning now to FIG. 8, a further modification of the While mercury and water have been given as examples of fluids suitable for use in the fluidic memory unit of this invention, it is to be understood that any of a wide variety of other mutually distinguishable and generally immiscible fluids may be selected. It is further contemplated that gases or a combination of a gas and a liquid might be used although non-compressible fluids (i.e., liquid) are generally preferred. The principal consideration is that. once introduced into the memory tube, each quanta or segment of fluid retains its integrity and identity or, in the .event each segment is composed of more than one fluid, (FIG. 6) that the fluid portions of such segment remains distinct and identifiable. Stated differently, the forces tending to keep each segment of fluid intact, which may be referred to as restoring forces, must exceed the forces tending to intermix the advancing fluid segments, such forces being referred-to as the disturbing forces or disruptive forces. In general, where the fluids are liquids and the memory tube is substantially horizontal, the primary disruptive forces are gravity and friction and the countervailing (and dominating) restoring force is the surface tension at the liquid-tube interface and at the liquid-liquid interface. If, on the other hand, the tube is vertically oriented then the primary restoring force is the surface tension at the interface between the dissimilar liquids.

It is further contemplated that a wide range of detachable physical-properties may be used to distinguish between the different fluids. That is, not only optical density, as explained herein, may be used, but also dielectric constant, magnetic reluctance or remanence, radioactivity, photoluminescence, cathodoluminescence or conductivity, depending largely on the characteristics of the fluids selected.

Having thus described a number of embodiments of the invention in detail, it will be obvious to persons skilled in the art that certain modifications and changes may be made in the system of fluids other than those described; and it is, therefore, intended that all such modifications and equivalents be covered as they are embraced within the spirit and scope of the appended claims.

I claim:

1. A fluidic memory for storing a representation of a digital signal comprising: a plurality of pump means, each receiving a fluid having a sensible characteristic representative of a data level of said signal, selection means receiving said digital signal for energizing a selected one of said pump means receiving a fluid representative of the data level of said signal to pump a quantum of its associated fluid, and storage means receiving in sequence the fluids pumped from said pump means for storing said fluid quanta in the order selected.

2. The system'of claim 1 characterized by said selection means energizing selected ones of said pump means to effect a single stroke thereby to store a predetermined quantum of fluid for each received sequential signal.

3. The system of claim 2 wherein said storage means includes a tube further characterized by said fluid quanta being stored in contiguous relation with adjacent of said quanta in said tube whereby a force transmeans, the sequential occurence of said signal being representative of the stored data pattern.

5. The system of claim 4 further comprising scanning sensor means located at spaced intervals along said tube, said scanning sensor means sensing the stored fluid pattern at a rate greater than the propagation rate of said fluid quanta.

6. The system of claim 4 further comprising a plurality of said tubes, each of said tubes storing in parallel a pattern of fluid quanta representative of sequentially occuring received digital signals, and further comprising scanning sensor means for sequentially generating a signal representative of a given location on each of said tubes, whereby the content of said tubes may be read in parallel.

7. The system of claim 3 characterized by each data level being represented by two fluid quanta, the order in which said fluid quanta representing a given information bit exist in said tube being representative of said data level.

8. The system of claim 3 wherein each of said fluids has a different optical transmissivity and wherein said sensor means includes a source of light intersecting the fluid in said tube and light responsive means receiving the light transmitted through said fluid in said tube for generating a signal representative thereof, said signal also being representative of the stored data level corresponding to the fluid passing before said light source.

9. The system of claim 1 wherein said storage means includes an elongated tube of closed section having an input terminal and an output terminal, said pump means introducing said selected fluid quanta at said input in contiguous relation with preceeding ones of said quanta.

10. The system of claim 9 further comprising reservoir means connected to the output terminal of said tube for receiving the fluid quanta exhausted therefrom, said fluids having different densities and being immiscible whereby said fluids separate into stratified layers in said reservoir, and return conduit means coupled to spaced-apart locations on said reservoir for coupling said separated fluids back to their associated pumps.

11. A method comprising: receiving a digital input signal having a discrete number of data levels, selecting one of a plurality of fluids having distinguishable characteristics according to the received digital signal, each fluid corresponding to a different level of said signal, and introducing said selected quanta of fluids into storage means in sequential time relation while maintaining the spacial relation of said sequentially introduced quanta, said spacial relation being representative of said input electrical signal.

12. The method of claim 11 wherein said step of introducing selected quanta of fluids comprises predetermined quantities of immiscible fluids into an elongated conduit having a closed cross-section.

13. The method of claim 12 wherein said received signal is a binary signal and wherein said plurality of fluids comprise two immiscible fluids having substantially different optical transmissivity characteristics.

14. The method of claim 11 wherein said step of introducing said selected quanta of fluids includes pumping predetermined volumes of said selected fluids into a conduit, and further comprising the step of generating a time base signal representative of the propagation of said quanta of fluids through said conduit.

15. A method for coding information which comprises the steps of selecting a plurality of diverse fluids to be non-miscible under the conditions of their use; feeding said fluids into a small diameter data storage line such that one fluid serves as a data separation fluid to separate bits of data and a characteristic of at least one other of the said fluids is indicative of data bits. 

1. A fluidic memory for storing a representation of a digital signal comprising: a plurality of pump means, each receiving a fluid having a sensible characteristic representative of a data level of said signal, selection means receiving said digital signal for energizing a selected one of said pump means receiving a fluid representative of the data level of said signal to pump a quantum of its associated fluid, and storage means receiving in sequence the fluids pumped from said pump means for storing said fluid quanta in the order selected.
 2. The system of claim 1 characterized by said selection means energizing selected ones of said pump means to effect a single stroke thereby to store a predetermined quantum of fluid for each received sequential signal.
 3. The system of claim 2 wherein said storage means includes a tube further characterized by said fluid quanta being stored in contiguous relation with adjacent of said quanta in said tube whereby a force transmitted to one of said quanta will be exerted on the remainder of the same.
 4. The system of claim 3 further comprising sensor means associated with said tube for generating a signal representative of the fluid passing before said sensor means, the sequential occurence of said signal being representative of the stored data pattern.
 5. The system of claim 4 further comprising scanning sensor means located at spaced intervals along said tube, said scanning sensor means sensing the stored fluid pattern at a rate greater than the propagation rate of said fluid quanta.
 6. The system of claim 4 further comprising a plurality of said tubes, each of said tubes storing in parallel a pattern of fluid quanta representative of sequentially occuring received digital signals, and further comprising scanning sensor means for sequentially generating a signal representative of a given location on each of said tubes, whereby the content of said tubes may be read in parallel.
 7. The system of claim 3 characterized by each data level being represented by two fluid quanta, the order in which said fluid quanta representing a given information bit exist in said tube being representative of said data level.
 8. The system of claim 3 wherein each of said fluids has a different optical transmissivity and wherein said sensor means includes a source of light intersecting the fluid in said tube and light responsive means receiving the light transmitted through said fluid in said tube for generating a signal representative thereof, said signal also being representative of the stored data level corresponding to the fluid passing before said light source.
 9. The system of claim 1 wherein said storage means includes an elongated tube of closed section having an input terminal and an output terminal, said pump means introducing said selected fluid quanta at said input in contiguous relation with preceeding ones of said quanta.
 10. The system of claim 9 further comprising reservoir means connected to the output terminal of said tube for receiving the fluid quanta exhausted therefrom, said fluids having different densities and being immiscible whereby said fluids separate into stratified layers in said reservoir, and return conduit means coupled to spaced-apart Locations on said reservoir for coupling said separated fluids back to their associated pumps.
 11. A method comprising: receiving a digital input signal having a discrete number of data levels, selecting one of a plurality of fluids having distinguishable characteristics according to the received digital signal, each fluid corresponding to a different level of said signal, and introducing said selected quanta of fluids into storage means in sequential time relation while maintaining the spacial relation of said sequentially introduced quanta, said spacial relation being representative of said input electrical signal.
 12. The method of claim 11 wherein said step of introducing selected quanta of fluids comprises predetermined quantities of immiscible fluids into an elongated conduit having a closed cross-section.
 13. The method of claim 12 wherein said received signal is a binary signal and wherein said plurality of fluids comprise two immiscible fluids having substantially different optical transmissivity characteristics.
 14. The method of claim 11 wherein said step of introducing said selected quanta of fluids includes pumping predetermined volumes of said selected fluids into a conduit, and further comprising the step of generating a time base signal representative of the propagation of said quanta of fluids through said conduit.
 15. A method for coding information which comprises the steps of selecting a plurality of diverse fluids to be non-miscible under the conditions of their use; feeding said fluids into a small diameter data storage line such that one fluid serves as a data separation fluid to separate bits of data and a characteristic of at least one other of the said fluids is indicative of data bits. 